Telegraphone.



No. 882,329. PATENTED MAR. 17, 1908. J. A. LIEB.

TELEGRAPHONE.

APPLICATION FILED MAR. 25. 1907.

QVT/nemco M 4%; M a

different relative resulting movement.

of the United States, residin face of which the record is made.

UNITED STATES ATENT OFFICE.

JOHN A. LIEB, OF NEW YORK, N. Y., ASSIGNOR TO AMERICAN TELEGRAPHONE COMPANY,

' A CORPORATION OF THE DISTRICT OF COLUMBIA.

TELE GRAPHONE.

Specification of Letters Patent.

Patented March 17, 1908.

To all whom it may concern:

Be it known that I, JOHN A. LIEB, a citizen at the city of New York, in the borough of Brooklyn and State of New York, have invented certain new and useful Improvements in Tele raphones, of which the following is a fufi, clear, and exact description.

My invention relates to a form of apparatus for ma netically recording and reproducing sound undulations. One form of apparatus in actual use is the telegraphone,

and the featuresof the present invention are ap licable' thereto in certain of its forms.

n order to make a magnetic record of sound undulations, it is necessary to have a steel body passing in a continuous movement with respect to a given point at which the recording and reproducing devices are located. This has been accomplished by steel wires, by steel plates or disks and in other ways.

By the present invention I make use of a hollow drum or body upon the interior sur- In practice the sheet or plate of steel is sprung into the hollow interior of the drum so as to produce a removable surface therein on which the record may be made and afterwards withdrawn and replaced by another. This arrangement is particularly advantageous because a steel plate may be sprung into a hollow drumso as to become firmly allixed thereto in proper contacting relation byno means or force other than its own resiliency. It will be evident that there is a constant s eed of travel of the recording surface, that t e entire surface is available for use, and the record can be stored or shipped compactly in rectangular boxes or ackages. lhe steel sheet or plate may be of uniform thickness but the best practical results are obtained by having it thicker at the middle than at the ends, as will later more fully appear. It is obvious that when a plate of this form is sprung into a hollow drum that its ends may fail in either abutting or overlapping relation without producing a seam or ridge of sufficient size to noticeably interfere with the action of the instrument. The recording and reproducing magnet may be moved with respect to the medium or the medium with respect to the magnet, or both may have a movement so as to produce a In esignated bv the same reference sign, 1 denotes a hollow cylindrical drum or member, the interior surface 2 of which is finished to a perfect surface of revolution. The member 1 has a trunnion 3, constituting a shaft or spindle therefor, the axis of which is exactly concentric to the interior surface 2. 4 denotes a journal or hearing for the spindle 3, and 5 indicates a pulley by which the frame 1 is rotated. ,It is to be understood that the means by which the frame 1 is supported and rotated are merely examples of a very simple practical way of securing the desired functions.

Within the frame 1, and supported against the interior surface 2 thereof, is placed the steel sheet or band 6, which constitutes the most essential feature of the present invention. As already stated, this sheet or band is normally rectangular, with a width corresponding to the length of the elements of the cylindrical surface 2, and a length corresponding to the circumferential extent of such surface, or possibly slightly less than such circumferential extent. The end edges of the plate 6 are finished square and true. This plate is bent so that it can be inserted into the interior of the drum 1, and then springs or expands outward until its edges pass from overlapping into abutting relation, as shown at 7, in Fig. 2. The resiliency of the plate 6 locks it securely within the drum 1. This engagement is made so tight and firm in practice that an exactly true cylinder of revolution is produced. When the plate is properly contained within the drum 1 in this way, the strains due to its elasticity cause it to cling closely to the surface of the drum. In one form of my invention later described the strains are all circumferential and equal at all points, so as to insure the formation of the perfect-cylindrical outline re uired.

he interior surface of the plate 6, which is thus constrained into a perfectly cylindrical form, is made use of as the recording and reproducing medium. For this purpose it is merely necessary'to move the drum rotarily and spirall' w1th respect to the device which produces t e magnetization-.-

8 denotes a magnet for this purpose, having a pole 9, and whichis mounted on an arm 10, rojecting from a carriage 11, movable on the rods 12.

13 denotes an arm projecting from the carriage 11, and which has teeth 14, adapted to engage and mesh with spiral threads 15, on the exterior surface of the drum 1. In order to have the carriage freely movable indeendent of the threads, the arm 13 is not rigreproducing sound undulations comprising a 1dly held to the carriage, but. is capable of spring resisted movement thereon by virtue of the pivot 16, and the spring 17.

18 denotes a handle for moving the arm 13. It is obvious that these details of the carriage and parts for supporting and moving the reproduction device are merely a convenient practical construction, and may be widely varied to suit diflerent requirements.

The operation will be sufficiently .understood from the preceding description. The drum 1 rotates and the carriage 11 is drawn into the same by the engagement of the threads 14, 15. In this movement the pole 9 pursues a helical ath on the interior cylindrical surface of the plate 6, and in case the magnet 8 is in a circuit traversed b a fluctuating current, a magnetic recoil o the undulations is made. In reproducing the record it is merely necessary to repeat these movements with the magnet 8 in circuit with a telephone receiver.

In some cases it is referable to have the plate 6 of unequal thicliness in a longitudinal direction being thicker at the middle than at'the two extremities. This construction is illustrated in Fig. 3. The idea of this form is to insure its bending nicely into the cylindrical outline re uired by its own elastlclty1 acting against t e containing walls of the ollow drum in which it is received. With this form of theinvention it is imniaand a recording and reproducing device 00- operating with such surface.

3. A-means for magnetically recording and 4 steel plate sprung into .a hollow "supporting drum or member and constrained into-cylindrical outline therein by its own resiliency.

4. A means for magnetically recording and re roducing sound undulations comprising a ho low drum having an interior surface of revolution, a steel plate closely received against said surface of revolution and held thereto by its own resiliency.

5. In an apparatus for magnetically recording and reproducing sound undulations, a hollow drum having an interior face of steel, means for rotating said drum on its axis, a carriage movable in a direction parallel to the axis of said drum, a recording and reproducing device connected with said carnage and cooperating with the interior surface of said drum, and means of cooperating with the outside of said drum for feeding said car-. riage with respect thereto.

6. In an apparatus for magnetically recording and reproducing sound undulations, a hollow drum or body and a steel sheet or plate sprung therein, said late being of diminishing thickness towar s its ends.

In Witness whereof, I subscribe my signature, in the presence of two witnesses.

.- JOHN A. LIEB.

Witnesses:

' WALDO M. CHAPIN,

MAY BIRD. 

